Abstract

Objective: Essential tremor (ET) is a common neurological disorder that has been associated with 60% increased risk of developing dementia. The goals of the present study were to: (a) learn whether individuals with advanced ET symptoms seeking deep brain stimulation (DBS) surgery would fall into distinct cognitive subgroups, and (b) learn how empirically derived subgroups map onto criteria for mild cognitive impairment (MCI). Method: Patients with ET (N = 201; mean age = 68.9 ± 8.9 years) undergoing pre-surgical evaluation for DBS completed a multi-domain neurocognitive assessment consisting of memory, executive function, visuospatial skill, language, and processing speed. Two cluster analytic approaches (K-means, hierarchical) were independently conducted to classify cognitive patterns using domain composites. Demographics, clinical characteristics, and proportion of cases meeting neuropsychologically defined criteria for MCI were examined among clusters. Results: A three-cluster solution reflected a Low Executive group (N = 64), Low Memory Multi-Domain group (N = 41), and Cognitively Normal group (N = 96). The Cognitively Normal group was older and more educated, with a higher Dementia Rating Scale-2 score. In total, 27.4% of participants met criteria for MCI. Of the MCI cases, most were in the Low Executive (41.8%) or Low Memory Multi-Domain groups (49.1%). In the latter, 65.9% of its members were classified as MCI versus 35.9% in the Low Executive group. Conclusions: Our study identified three cognitive subtypes of ET patients presenting for DBS. Future work should examine the subgroups for progression to dementia, particularly the Low Memory Multi-Domain subgroup which may be at highest risk.

摘要

目的：特发性震颤 (ET) 是一种常见的神经系统疾病，与 60% 的痴呆风险增加相关。本研究的目标是：(a) 了解寻求深部脑刺激 (DBS) 手术的晚期 ET 症状的个体是否会属于不同的认知亚组，以及 (b) 了解根据经验得出的亚组如何映射到轻度认知障碍的标准（MCI）。方法： 接受 DBS 术前评估的 ET 患者（N = 201；平均年龄 = 68.9 ± 8.9 岁）完成了多领域神经认知评估，包括记忆、执行功能、视觉空间技能、语言和处理速度。独立进行两种聚类分析方法（K均值、分层）来使用领域组合对认知模式进行分类。对各集群之间的人口统计、临床特征和符合神经心理学定义的 MCI 标准的病例比例进行了检查。结果：三簇解决方案反映了低执行力组 ( N  = 64)、低记忆力多域组 ( N  = 41) 和认知正常组 ( N  = 96)。认知正常组年龄更大、受教育程度更高，痴呆评定量表 2 得分更高。总共有 27.4% 的参与者符合 MCI 标准。在 MCI 病例中，大多数属于低执行力组 (41.8%) 或低记忆多域组 (49.1%)。在后者中，65.9% 的成员被归为 MCI，而 35.9% 的成员被归为低执行力组。结论：我们的研究确定了接受 DBS 治疗的 ET 患者的三种认知亚型。未来的工作应该检查亚组是否进展为痴呆，特别是低记忆多域亚组，该亚组的风险可能最高。